Attachment for telescopes.



H. C. MUSTIN.

ATTACHMENT FOR TELESCOPES.

APPLICATION FILED JAN. 16. 1915.

1,153,945. ParentedSept. 21, 1915.

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H. C. MUSTIN. ATTACHMENT FOR TELESCOPE-IS.

APPLICATION FILED 1AN.16.1915.

PatentedSept. 21, 1915.

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HENRY C. MUSTIN, OF THE UNITED STATES NAVY.

ATTACHMENT FOR TELESCOPES.

Specification of Letters Patent.

Patented Sept. 21,1915.

Application filed January 16, 1915. seal in). 2,740.

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to telescopes, and has for its object to provide means capable of protectingthe objectives of said telescopes from rain, spray and the splashes of waves, smoke or any other liquid or fluid which might contact with said objectives, and thereby obscure the vision.

The invention is particularly useful for sighting on naval guns, and also on periscopes of submarine boats.

Further objects of this invention are to produce a device of this nature which will not appreciably change the direction of the line of sight through the telescope; one that will not impair the distinctness of the image; and one that will not reduce materially the field of view of the telescope.

With these and other objects in view, the invention consists in the novel details of construction and combinations of parts more fully hereinafter disclosed and particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of this specification: Figure l is a diagrammatic view of a telescope with my invention attached thereto; Fig. 2, is an enlarged longitudinal sectional view through the attachment and the objective of the telescope; Fig. 3, a sectional View taken on the line 33 of Fig. 2; Fig. 4c, is a face view of the attachment with the cover removed showing the central shaft in section, and Fig. is a detail of one means by which the cover may be attached to the body of the attachment.

1 represents the body of the telescope; 2 the usual objective; 3 a screw threaded flange rigid with the diaphragm or plate 4 and fitting the objective end of the telescope, as shown, while 5 represents an aperture through said plate 4 whose center is located in the optical axis of the telescope.

The plate at is preferably provided with a flange 6 adapted to receive a flange 7 of a second plate or diaphragm 8 provided with an aperture 9, the center of which is also in the optical axis of the telescope; and this plate 8 is provided with a flange 10 adapted to receive a casing 11 provided with an aperture 12 the center of which likewise Coin cides with the optical axis of theteleseope.

13 designates screws. or other fastenings j oiningthe parts as shown. Passingthroug'h the plates 4 and 8 is the shaft 14 on which is mounted the gear 15 'n1eshin'g with the gear 16 mounted'on theshort shaft 17, and which gear 16 meshes with the gear 18 mounted on 'the power shaft 19'carrying the power 'wheel'QO, as best illustrated in Fig. .2. Also mounted on the shaft 141 is a pair of disks '21 and '22 between which are mounted vanes 23 which are preferably straight but maybe curved if desired. The disks 2 1 and 22 are rigid with each other and are provided with a series of registering apertures 24, preferably as m'any apertures as there are vanes; and each aperture in'each disk is adapted to register with the apertures 5, 9 and 12 when the'disks and varies are turned on the shaft 14.

The plate 8 is provided with an annular flange 40, and the casing 11 has a similar flange 11, into which flanges the disks 2 1 and 22, respectively, loosely fit, as shown. The casing 11 is also provided with a plurality of holes 25, four being shown, and one of which is preferably located at the lowest p'oi'nt'of said casing when the telescope is in use. This lowest hole permits the escape of any liquid that may find its way inside the casing when the vanes are not in motion, and each of the holes permits the escape of any liquid that may be forced outwardly by the vanes 23.

It is 'often desirable to entirely inclose the parts of the apparatus, and "for this purpose there is provided the cap 30, provided with holes 31 adapted in one position to register with the said holes in the casing 11, and in another position as illustrated in Fig. 3, to close said holes 25. In order to permit relative motion between the casing 11 and cap 30, the latter is, or may be, provided with elongated slots 32 (see Fig. 5) through which the screws 13 ma pass, and thereby permit the said cap to revolve around the casing sufficiently to close all of said holes 25 and 81, as will be readily understood.

The cap 30 is also provided with a hole 3% which registers with and closes the aperture 12 in the casing 11, when the above relative motion is produced j V I v The operation will be clear from the foregoing, but it may be summarized as follows :Supposing the cap 30 to be in position to cause its holes 31 to register with the holes 25 in the casing, and supposing a sufficient speed to be imparted to the power wheel 20, it is evident that the disks 21 and 22 will be rotated and the apertures 24: therein will be rapidly moved past the apertures 5, 9 and 12. It is further evident that if this motion is sufficiently rapid, the vision through the objective and said apertures 5, 9 and 12 will not be seriously impaired. It is likewise evident that ifv water from rain, spray or from the splashes of waves should strike the objective end of the. telescope while said disks are in rapid motion, that owing to centrifugal force, the vanes 23 would not permit said water to come into contact with the objective. That is to say, any water that may enter the casing, will at once be carried around at a high speed by the vanes, and will be caused to pass by the apertures 9 and 5, and out through the holes in the casing, thus leaving the objective always dry. Actual trial has demonstrated, that, in fact, water may strike the objective j end of the telescope with considerable force, without even causing a film tosettle on the objective. It is very desirable, however, that the distinctness of the telescopic image be not impaired, and it is found that if for the sighting telescopes now' in use in the United States Navy, the diameter of the holes 5, 9 and 12 is made about ninety-eight thousandths (.098) times the magnifying:

power of the telescope that the distinctness 'of the image is not impaired to any appreciable extent, although in the day time there will be a slight shading of the object viewed,

especially if the speed of rotation is not high. That is to say, the aperture of this size will give the telescope an exit pupil of .098 inches, the size most suitable for distance vision in the day time. In order to get up sufficient speed forthe vanes 23, any suitable connection may be' employed between the power shaft 19 but the shaft 14, and the two gears shown are preferred.

When the disks 21, 22, are revolved at a speed of about 2000 revolutions per minute 7 or higher, an observer looking through the telescope will observe no flickering of the image, or other signs of the rapid occultations except the slight shading effect above. No deviation of the line of sight whatever occurs, and therefore no aiming errors due to such deviations are encountered, which makes this device especially useful on guns.

The power wheel 20 is shown merely to illustrate an experimental method of imparting power to the vanes; in practice a flexible shaft connection will be employed, although it wouldcome within the limits of this invention to employa small electric motor on the telescope itself, or to employ any suitable means whatever for imparting motion to said vanes.

I It will be observed that as seen in Fig. 3, the vanes are supposed to rotate in the direction of the hands of a clock, as indicated. by the arrow, and that the apertures 24., are all displaced in the same direction, so that said holes are closer to the receding edges of the vanes than to their advancing edges. This. is the most advantageous position of said holes when the rotation is as indicated.

It is evident, that various changes in the construction and arrangement of parts could be made by those skilled in the art without departing from the spirit of this invention, and therefore I do not wish to be limited to the exact device shown except as may bere therewith adapted to prevent water from contacting with said objective, said means being provided with a pluralityof apertures,

substantially as described.

3. In a telescope the combination of an objective; rotating means provided with vanes and an aperture 'coacting with said objective; and means to rotate said rotating means substantially as described.

4. In a telescope the combination of an objective; means provided with an aperture through which an object may be viewed coacting with said objective; and rotating means adapted to move past said aperture, substantially as described.

5. An attachment for telescopeshaving an aperture through which an obj ect'ma'y be viewed; rctating means adapted to occult said aperture; and means to rotate at a high speed said rotating means, substantially as.

described.

6. In a telescope the combination with an objective; of a plate covering the same provided with an aperture through which an object may be viewed; rotating means provided with an aperture adapted to register at intervals with the aperture in said plate; and means associated with'said rotating means adapted to force by centrifugal action, any water that may come in contact with said rotating means past said first mentioned aperture, and thereby prevent said water from touching said objective, substantiallv as described.

7. In a telescope the combination of means comprising an objective through which an object may be viewed; and means adapted through centrifugal action to protect said objective from the contact of water to which it would be otherwise exposed, substantially as described.

8. In a telescope the combination of means comprising an objective through which an object may be viewed; and means comprising a plurality of rotating vanes with holes near the receding edges of said vanes, said second means adapted through centrifugal action to protect said objective from the contact of water to which it would be otherwise exposed, substantially as described.

In testimony whereof, I alfiX my signature, in presence of two Witnesses.

HENRY C. MUSTIN.

Witnesses ERNEST l/VILKINsoN, EDWIN J. BELLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

